e12 master cylinder w/ stock brakes?

[autoaloha]

hey all, after getting my car together this weekend I find the stock master cylinder weeping from the tell-tale drain. So, I assume it's blown. No one on Oahu has a new master cylinder for my 2002a- but there is a e12 master cylinder. I know this is one piece of the 'volvo girling upgrade', can I simply use this master cylinder until I source the other parts? What will be the result? Firmer brakes I assume, bigger MC with smaller brakes means less pedal travel right?

Please tell me this is ok!

thanks

-ken

[TobyB]

If it's a larger bore, then you'll get less pedal travel with

higher pedal effort.

If you're ok with it, then it's fine.

It's a worthwhile excercise to compare the area

of the 2 in percent. As in, if it's 20% more area,

it'll probably be no issue, but if it's 100% more,

it's going to take a LOT of effort to even slow down a bit.

hth

t

[///mChris]

Don't forget a residual pressure valve. You don't want your drums pushing too much fluid back into the reservoir.

[autoaloha]

Don't forget a residual pressure valve. You don't want your drums pushing too much fluid back into the reservoir.

What kind/brand/mounting are people generally using? If anyones got a link to this I'd really appreciate. I think I can run without it until I find the right pieces for rear brake setup.

I ended up using some VW reservoir grommets with the e12 528i MC. It's installed, bled and ready to go now. Just gotta rebuild my recaro and I'm driving...to the junkyard to loot a 320i and a volvo...

-ken

[///mChris]

You should be able to take the "pre-pressure valve" off your old master cylinder and reuse it.

http://www.realoem.com/bmw/showparts.do?model=2552&mospid=47140&btnr=34_0804&hg=34&fg=25

As to the spec on it.. I'd only have to guess it's a pretty small one.

[autoaloha]

You should be able to take the "pre-pressure valve" off your old master cylinder and reuse it.

http://www.realoem.com/bmw/showparts.do?model=2552&mospid=47140&btnr=34_0804&hg=34&fg=25

As to the spec on it.. I'd only have to guess it's a pretty small one.

That's what I had planned on doing, but it's way too big. The fitting(same as front supply and return) without that valve fits in perfect though... I'm gonna have to develop a work around.

[///mChris]

Residual pressure valve is pretty important, but can be added any place in that line.

For drum brakes to function correctly there needs to be a 10 lb residual pressure valve in the system. This residual valve will maintain a 10 lb pressure on the drum brakes to counter the spring presure in the system. This keeps the shoes out close to the drum giving a higher firmer pedal. Without the residual valve in the drum system, every time you step on the pedal all the fluid goes to moving out the shoes before drum contact.

http://www.mpbrakes.com/technical-support/troubleshooting-disc-drum-01.cfm